1. Field of the Invention
The invention relates generally to a chip-like polar electrical component of a type designed for surface mounting, wherein the positive and negative leads are arranged to prevent electrical contact with pads on a printed circuit board in the event said device is mounted to a printed circuit board with its polarity reversed, or otherwise displaced from its intended position.
2. Description of the Prior Art
Chip-like electrical components, sometimes referred to as leadless components and/or surface mounted devices, are well known in the prior art. While most such chip-like components are not polar devices, the solid electrolyte capacitor among others is a polar device. The present invention, while not limited to solid electrolyte capacitors, will be described in terms of these devices.
The prior art with respect to solid electrolyte chip capacitors is well known. Among the recent U.S. patents which describe this prior art in some detail are U.S. Pat. Nos. 4,510,554 and 4,539,623, both assigned to Matsushita Electric Industrial Co., Ltd. The prior art is also discussed in U.S. patent application Ser. No. 670,088, filed Nov. 9, 1984, and assigned to the assignee of this application. This latter application is incorporated herein by reference.
In view of the fact that the construction of the solid electrolyte chip capacitor is thoroughly disclosed in the prior art referenced above, such a discussion will be omitted from the present application.
Prior art devices available commercially and disclosed in the patent art have failed to solve one significant problem which has arisen with the development of automatic placement equipment for the surface mounting of chip components. If a polar device such as a solid electrolyte tantalum capacitor is surface mounted on a printed circuit board in such a way that it is rotated 180.degree. from the intended orientation of its positive and negative terminations, the device can short, thereby causing a failure of the device, or the circuit, and possible burn-out of the printed circuit board. The configuration of the leads and/or terminals and the corresponding pad area on the printed circuit board disclosed herein can prevent such a failure in the event of misplacement or other misorientation of a surface mounted polar device.